The book has two parts. The first reconstructs the history of the Holy See’s involvement with the issue of contraception between 1963 and 1968, the year Humane vitae was published. The second part is a selection of original documents from the Vatican archives made available to the special commission.
Marengo presents some important new facts about the drafting of Humanae vitae. To begin with, an earlier version of the encyclical was approved by Paul VI and scheduled for publication on May 23, 1968. That version, titled De nascendae prolis, had been written by Fr. Mario Luigi Ciappi, OP, and was a revision of a late 1967 text from the Congregation for the Doctrine of the Faith. But the French and Spanish translators expressed a very negative assessment of Ciappi’s text, and on the advice of Monsignor Benelli, number two at the Secretariat of State, Paul VI decided to withdraw De nascendae prolis. The encyclical was hastily rewritten between May and July of 1968 under the direction of Fr. Benoit Duroux, OP, consultor of the CDF. Paul VI supervised this redrafting, made numerous changes to the text—especially in its pastoral section—and approved the new version of the encyclical on July 8, 1968. He also added “humanae” to the original title Vitae tradendae munus. (Marengo’s book gives us Duroux’s text along with Paul VI’s final changes). The two prelates who had a key role throughout the entire drafting of the encyclical were Monsignor Carlo Colombo, auxiliary bishop of Milan, and Paul-Pierre Philippe, OP, secretary of the CDF.
Paul VI’s initial eagerness to consult with other prelates is an important part of the story. As Marengo makes clear, Paul VI had not wanted to act alone on this issue. But in 1966 a well-known rift emerged in the birth-control commission set up by John XXIII between a majority that wanted the church to relax its prohibition on contraception and a minority who wanted to maintain it. It was in the wake of this split that Paul VI finally decided to disregard the advice of most of the bishops who had sent him their suggestions after the synod. Marengo notes that the people Paul VI chose to draft the encyclical made little effort to listen and respond to the worries of the commission’s majority. The final text of Humanae vitae was essentially a product of theologians of the former Holy Office, and bore little trace Vatican II’s reflection on marriage in Gaudium et spes.
All this helps us place Humanae vitae in the history of papal teaching on birth control—from Paul VI to Francis. To judge from Marengo’s book, Archbishop Karol Wojtyła (later Pope John Paul II) did not have much impact on the drafting of Humanae vitae. But he did make some notable suggestions about the pastoral dimension of the text, and showed a keen interest in making sure that the encyclical did more than simply reaffirm the teachings of Pius XI and Pius XII. In a book  on marriage by the young Joseph Ratzinger, reissued last month in Italian translation, we find the future Benedict XVI criticizing Humanae vitae’s theology of matrimony. (Ratzinger wrote the book in 1967 but it didn’t come out until 1969, a year after the publication of Humanae vitae.) Reading what these two future popes had to say about the encyclical before and immediately after its appearance reminds us that its theology was not the undebatable article of faith that it has since become for many conservative Catholics.
Marengo’s book is a milestone in the continuing effort to understand the history of the most controversial encyclical in modern times. Other questions remain, and they will be answered when other scholars, independent of the Holy See, are given access to the same set of documents Marengo’s special commission was allowed to study.